From aab004def227e7b02de1461acc92d38317d99160 Mon Sep 17 00:00:00 2001
From: Edward Faulkner <edward@eaf4.com>
Date: Thu, 21 Nov 2024 10:08:42 -0500
Subject: [PATCH] Support esm babel plugins

This adds test coverage for a vite app with a babel plugin published as an ES module and fixes the one place (in our esbuild resolver) where we were preventing that from working.
---
 packages/vite/src/esbuild-resolver.ts  | 10 ++++----
 tests/scenarios/vite-internals-test.ts | 34 ++++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 5 deletions(-)

diff --git a/packages/vite/src/esbuild-resolver.ts b/packages/vite/src/esbuild-resolver.ts
index e3ee2bc20..683864139 100644
--- a/packages/vite/src/esbuild-resolver.ts
+++ b/packages/vite/src/esbuild-resolver.ts
@@ -1,5 +1,5 @@
 import type { Plugin as EsBuildPlugin, OnLoadResult, PluginBuild, ResolveResult } from 'esbuild';
-import { transform } from '@babel/core';
+import { transformAsync } from '@babel/core';
 import core from '@embroider/core';
 const { ResolverLoader, virtualContent, needsSyntheticComponentJS, isInComponents } = core;
 import fs from 'fs-extra';
@@ -17,15 +17,15 @@ export function esBuildResolver(): EsBuildPlugin {
   let resolverLoader = new ResolverLoader(process.cwd());
   let preprocessor = new Preprocessor();
 
-  function transformAndAssert(src: string, filename: string): string {
-    const result = transform(src, { filename });
+  async function transformAndAssert(src: string, filename: string): Promise<string> {
+    const result = await transformAsync(src, { filename });
     if (!result || result.code == null) {
       throw new Error(`Failed to load file ${filename} in esbuild-hbs-loader`);
     }
     return result.code!;
   }
 
-  function onLoad({ path, namespace }: { path: string; namespace: string }): OnLoadResult {
+  async function onLoad({ path, namespace }: { path: string; namespace: string }): Promise<OnLoadResult> {
     let src: string;
     if (namespace === 'embroider-template-only-component') {
       src = templateOnlyComponent;
@@ -40,7 +40,7 @@ export function esBuildResolver(): EsBuildPlugin {
       src = preprocessor.process(src, { filename: path });
     }
     if (['.hbs', '.gjs', '.gts', '.js', '.ts'].some(ext => path.endsWith(ext))) {
-      src = transformAndAssert(src, path);
+      src = await transformAndAssert(src, path);
     }
     return { contents: src };
   }
diff --git a/tests/scenarios/vite-internals-test.ts b/tests/scenarios/vite-internals-test.ts
index 45981b9fc..e95d63c19 100644
--- a/tests/scenarios/vite-internals-test.ts
+++ b/tests/scenarios/vite-internals-test.ts
@@ -113,6 +113,16 @@ function buildViteInternalsTest(testNonColocatedTemplates: boolean, app: Project
       },
     },
     tests: {
+      unit: {
+        'babel-plugin-is-module-test.js': `
+          import { module, test } from "qunit";
+          module("Unit | babel-plugin-is-module", function () {
+            test("it ran", function (assert) {
+              assert.strictEqual("sample-transform-target", "sample-transform-result");
+            });
+          });
+        `,
+      },
       integration: {
         components: {
           'example-test.js': `
@@ -230,6 +240,30 @@ function buildViteInternalsTest(testNonColocatedTemplates: boolean, app: Project
     },
   });
   app.addDevDependency(v1ExampleAddon);
+
+  let babelPlugin = app.addDevDependency('babel-plugin-is-a-module', {
+    files: {
+      'index.mjs': `export default function({ types }) {
+        return {
+          visitor: {
+            StringLiteral(path) {
+              if (path.node.value === 'sample-transform-target') {
+                path.replaceWith(types.stringLiteral('sample-transform-result'));
+              }
+            },
+          },
+        };
+      }`,
+    },
+  });
+  babelPlugin.pkg.exports = {
+    '.': './index.mjs',
+  };
+  app.files['babel.config.cjs'] = editBabelConfig(app.files['babel.config.cjs'] as string);
+}
+
+function editBabelConfig(src: string): string {
+  return src.replace(/babelCompatSupport\(\),/, `babelCompatSupport\(\), 'babel-plugin-is-a-module',`);
 }
 
 function runViteInternalsTest(scenario: Scenario) {